ASI W9700493r1.0

Moon Miners' Manifesto

#99 October 1996

Section the Artemis Data Book


IN FOCUS: VentureStar Looks Good, But We Need C.A.T.S. Options

"Scrambled-X": Without demeaning Lockheed's winning X-33 design, it'd nonetheless be regrettable if we put all our eggs in one X-basket. The different candidate designs followed different combinations of assumptions. If only one set is tested, it is all too likely that we will get a good, not the best machine.

Henry Vanderbilt, in Space Access Update # 67, 7/11/'96 (Moon Miners' Review # 19), compared the X-33 offering with that of an inexpensive Delta Clipper follow-on that the Air Force would like to see funded. That comparison is given below. That the wisest policy is to pursue both options is clear.

Meanwhile, NASA will explore other promi-sing cheap access, reusable vehicle designs:

What about market forces? Lockheed Martin's expectations are high, that its vehicle, once opera-tional, could garner 80% of big load business! It is unlikely that other commercial players such as McDonnel Douglas and Arianespace would be happy with such dominance. We can look for competition, competition exploring other options. That's good.

Nor should we think that it is only a ques-tion of guaranteeing that we find the best combina-tion of features. Cheap Access To Space, CATS, is not a simple challenge with a single solution. It is a veritable tree of problems with both roots and branches spreading in different directions.

That the best CATS solution for large hard-ware payloads should by coincidence be the best CATS solutions for shipping materials to space that can be handled in any quantity, or that the best CATS solution for either should by some lucky quirk also be the best CATS solution for sending people, cabinsfull of people, to orbit - that coincidence would be bizarre.

More, Heinlein pointed out that once you are in orbit you are half way to anywhere, i.e. you may have solved only half your transportation problem. We need Cheap Access from LEO to GEO, from either to the Moon, from Earth and the Moon to Mars. These are all different sets of challenges that are likely to have unique solutions.

If all that the push for Cheap Access achieves is to make it easier and cheaper to put communications satellites in orbit, we will have spent a lot of energy without doing a thing to open the real space frontier.

In this issue, we take a look at just some of the many challenges and just some of the possible solutions. We're sure there are more problems and more good strategies - our purpose is to stimulate thought and vaporize the current simplistic hysteria over something that is more important and far-reaching than most CATS champions have let them-selves realize. In the end, CATS, the effort to insure ever cheaper access of everything we want to put in space to everywhere we want to go in space, will be an unending story. -- Peter Kokh

Space Access Society's analysis of relative merits of VentureStar X-33 and proposed Clipper follow-on:

  • X-33 does horizontal runway landing.
  • DC-XB/C would pursue vertical wingless small-pad powered landing.

  • X-33 uses medium-temperature metallic thermal protection.
  • DC-XB/C would use new high-durability high-temperature tile TPS.

  • X-33 tests new 'aerospike' rocket engines
  • DC-XB/C would demonstrate use of multiple traditional bell-nozzle engines, engine-out redundancy.

  • X-33 will pioneer use of complex multilobe composite propellant tanks
  • DC-XB/C insures against manufacturing/durability problems with simpler geometry tankage.

  • X-33 will test out low L:D low heat-load reentry profiles.
  • DC-XB/C will explore high-maneuverability high hypersonic L:D flight.

  • X-33 will need fixed operating bases, specialized ground-handling equipment for ship and payload
  • DC-XB/C will be aimed at more mobile operations out of small austere sites.

  • X-33 is a higher-risk higher-payoff approach, bundling new technologies into a complex package.
  • DC-XB/C takes a much more incremental approach - "build a little, test a little."


The "Tree of Cheap Access"

One thing almost everyone in the space activist community can agree on is the absolutely vital need to bring down drastically the cost of getting into space. But it is not commonly seen that this is not just one problem but several. Getting "what" into space? And just "where in space" are we talking about? The challenge is really multiplex. In In this mont's articles, we look at just some of the aspects.

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